Doctor Who actress Elisabeth Sladen has died of cancer at the age of 63, the BBC has confirmed.

She joined the programme in 1973 and became one of the most popular companions in her role as Sarah Jane Smith. In 2007 she was given her own spin-off series, the Sarah Jane Adventures, which introduced her to a new generation of fans.

Tributes have been pouring in for the Liverpool-born actress, known to her friends and family as Lis.

Russell T Davies, creator of The Sarah Jane Adventures, which won this year's RTS Award for best children's drama, said all those involved in the series had been left "reeling" at news of her death. He said: "I absolutely loved Lis. She was funny and cheeky and clever and just simply wonderful."

Sladen starred in Doctor Who alongside Jon Pertwee, the third doctor, and his successor Tom Baker. She then returned to the series on a number of occasions over the years before her own CBBC show was created, in which she starred as an investigative journalist trying to defend Earth from extraterrestrial threats.

It had not been widely known that she had been suffering from ill health. She leaves behind her husband, actor Brian Miller, and daughter Sadie.

Doctor Who lead writer and executive producer Steven Moffat said she was a "ferociously talented actress". He said: "'Never meet your heroes', wise people say. They weren't thinking of Lis Sladen. Sarah Jane Smith was everybody's hero when I was younger, and as brave and funny and brilliant as people only ever are in stories.

"But many years later when I met the real Sarah Jane - Lis Sladen herself - she was exactly as any child ever have wanted her to be. Kind and gentle and clever and a ferociously talented actress, of course, but in that perfectly English unassuming way."

CBBC controller Damian Kavanagh said: "I'm deeply saddened and shocked by the news of Lis's untimely death. Lis brought joy, excitement and a sense of wonder to her many fans in her role as Sarah Jane Smith. She was adored by our young audience and I know all of them will miss her as much as I will."

Her agent Roger Carey said: "She was not just a client, but a dear friend. She was so positive about life and her natural energy was intoxicating. She couldn't believe her luck when her career was resurrected in her own series."